Performance of Untreated Waste Cooking Oil Blends in a Diesel Engine

Untreated waste cooking oil (UWCO) is not a feasible diesel fuel. The major problems in engine operation are reported mainly due to UWCO’s high viscosity. To use UWCO's in diesel engine without modification, it is necessary to make sure that the oils properties must be similar to diesel fuel. In this study, UWCO that has been used several times for frying purposes is investigated for the utilization as an alternative fuel for diesel engines. In order to reduce the viscosity, the UWCO were blend with diesel. Two various blends of UWCO and diesel were prepared and its important properties such as viscosity, density, calorific value and flash point were evaluated and compared with that of diesel. The blends were then tested in a direct injection diesel engine in 10% and 30% v/v blends with a reference diesel fuel. Tests were performed under a set of engine operating conditions. It was found that blending UWCO with diesel reduces the viscosity. Blending of UWCO with diesel has been shown to be an effective method to reduce engine problems associated with the high viscosity of UWCO. The experimental results also show that the basic engine performance such as power output and fuelconsumptions are comparable to diesel and the emissions of CO and NOx from the UWCO/diesel blends were also found slightly higher than that of diesel fuel.